Generator device with overvoltage monitoring

Translation of description of equivalent WO 2009106453 A2

p0001Generator device with overvoltage monitoring

p0002The invention relates to a generator device, which is provided in particular for providing a necessary in the electrical system of a motor vehicle DC voltage, and which has means to an over-voltage monitoring.

p0003State of the art

p0004It is already known to regulate the output voltage of a generator by means of a generator controller. The output voltage of a generator depends on several factors, including the speed, the electrical load in the electrical system, the state of charge of the starter battery and the temperature are. In order to generate a constant voltage in the electrical system, the generator regulator controls the output voltage of the generator within predetermined limits. This system is controlled by an adjustment of the current flowing through the field winding of the generator excitation current. For adapting the exciting current, a change in the duty cycle of a PWM control provided by the controller-drive signal is carried out for a switching transistor.

p0005When using a high-side transistor as a switching transistor of the generator regulator of the excitation current from a DC voltage supply terminal B + is removed and conducted through the transistor to the excitation winding. The second terminal of the field winding is connected to ground supply.

p0006The alternating voltages produced at the phase voltage terminals U, V and W of the generator are in a sev- eral branches having rectifier arrangement rectified and provided to the electrical system of the motor vehicle and the Gleichspannungsversorgungs- said connection of the generator controller supplied.

p0007Furthermore, the generator controller is also connected to a phase of the voltage terminals of the generator in order to evaluate one of the phase voltages of the generator.

p0008The generator controller includes a regulator control, which provides a switching signal for the switching transistor of the generator controller and wherein the B + DC voltage and one of the phase voltages of the generator are fed as input signals to the DC voltage supply terminal.

p0009In today situated in series generator controls a function is implemented, which prevents a complete de-excitation of the generator changed in the event of load shedding. To this end, the controller controlling the generator controller monitors the phase voltage supplied to it and changes the switching signal for the switching transistor, when this phase voltage falls below a predetermined value.

p0010This phase voltage terminal of the generator controller is a mechanical, for example, bolted connection between the Regulator and the generator associated rectifier assembly, said-called phase voltage is tapped at a connection point between two diodes of a rectifier branch. a contact resistance can be at the said connection between the generator regulator and the rectifier arrangement due to various fault patterns adjust len. This results depending on the level of the contact resistance to a voltage drop. At this voltage drop the controller controller detects a presence of too low phase voltage. The voltage drop is un- in favorable cases so large that the phase voltage assigned intervention threshold of the regulator control is below. This results in an interference with the regulation by which the on-board network, an overvoltage can hen emergence.

p0011It is already known that the occurrence of such a surge ken by limiting the maximum permitted excitation current or duty cycle counteract. In practice, however, operating points may choose to surge despite this limitation.

p0012It is also already known, for the purposes of monitoring the phase lead resistor by modulation of the current in the scan path the resulting

p0013evaluate potential difference and if this exceeds a predetermined threshold, disable this control intervention. This procedure is complicated, since it is at a phase voltage signal to a high voltage signal dynamics.

ADVANTAGES OF THE INVENTION

p0015A generator device having the features of claim 1 has the advantage over the that during a control intervention of the phase voltage, an additional monitoring provided by the controller control switching signal is performed in order to avoid a state of excessive arousal and thus the occurrence of a surge in the electrical system. This is substantially achieved in that the generator regulator when during a control intervention of the phase voltage the connector on the operating voltage B + fitting filtered DC voltage for a predetermined time period a predetermined limit value Berschneider rides Ü, the control intervention of the phase voltage deactivated. Further advantageous characteristics of a generator apparatus according to the invention will be apparent from their exemplary explanation with reference to the drawing.

p0016drawing

p00171 shows a circuit diagram of a generator apparatus according to the invention. 2 shows a detailed diagram of the controller controlling the generator controller shown in FIG. 1

p0018description

p00191 shows a diagram of a Generatorvorrich- device according to the invention. The generator apparatus 11 shown includes a generator controller 1 and a generator unit 10, which provides a DC supply voltage for the electrical system 12 of a motor vehicle at its output.

p0020The generator unit 10 has a generator 2 and a rectifier arrangement. 9 The generator 2 includes a field winding 5 and not shown in detail, the phase windings, the device for example in the form of a star-connected or a delta connection are interconnected. The generator 2 is at its phase voltage terminals U, V and W AC voltages available, which are fed to the downstream rectifier device. 9 Alternatively, the illustrated embodiment may be a different number of phases and phase voltage connections.

p0021The rectifier arrangement 9 includes three branches, each of which has a series circuit of two diodes or other suitable components and another one of the

p0022is phase voltage terminals of the generator assigned. Of the phase voltage terminal U of the generator 2 is connected to the connection point between the diodes Dl and D4 of the first rectifier branch. The phase voltage terminal V of the generator 2 is ground point to a connection between the diodes D2 and D5 of the second

p0023Rectifier branch connected. Of the phase voltage terminal W of the generator 2 is connected to a connection point between the diodes D3 and D6 of the third rectifier branch.

p0024The cathodes of the diodes D4, D5 and D6 are connected together. There, the DC output voltage of the generator unit 10 is provided and passed to the electrical system 12th The anodes of diodes Dl, D2 and D3 are also connected together and are connected to ground.

p0025The phase voltage connection W of generator 2 is further through a terminal X of generator regulator 1 with the regulator controller 7 of the generator controller 1 and via a resistor R3 and a ground connection 3 of the generator controller with mass 4 in conjunction.

p0026The generator controller 1 has an operating voltage connection B + and other terminals DF, D and X on. Furthermore, the generator controller includes a regulator controller 7, which is provided with an evaluation logic. The regulator controller 7 is intended to provide a switching transistor 6, a PWM control signal available. The regulator controller 7 is also connected to the operating voltage connection B + and the ground connection 3 to ground. 4 Further, the controller 7 is control to the terminal X of the generator controller 1 in conjunction to receive a signal derived from the phase voltage terminal W of the generator 2 phase voltage signal.

p0027In addition, the device shown in Figure 1 has an excitation current circuit. This extends the operating voltage terminal B + of the generator controller 1 over the switching transistor 6 of the generator controller, the connection DF of the generator controller, the excitation coil 5, the terminal D of the generator controller and the ground connection 3 to ground 4. A freewheeling diode is either between the terminals D and DF of the generator controller 1 connected 8 or is used with a switching transistor, an active free wheeling.

p0028The regulator control 7, which with the operating voltage terminal B + and is connected through the terminal X with the phase voltage terminal W of the generator 2, the switch 6 is controlled by a control signal s in such a way that an exciting current flowing through the exciting coil 5, both of which is dependent on the operating voltage connection B + present DC voltage as well as temporarily from their supplied initiated through the terminal X phase voltage.

p00292 shows a more detailed representation of the regulator control 7. This has an operating voltage Istwertdetektor 7a, an operating voltage comparator 7b, 7c, a timer, a switching element 7d, a phase senspannungs detector 7e and an arithmetic unit 7f. The regulator controller 7 with the above-mentioned elements is preferably implemented gikschaltung in the form of a microcomputer or logic. The regulator controller 7 is provided to determine from the signals supplied to input a control signal S for the switching transistor 6 of the generator controller. 1

p0030The Eingangssig annals of computing unit 7f heard of

p0031Actual value of the + present at the operating voltage connection B Operating voltage which is present at the output of Betriebsspannungsistwertdetektor 7a. Furthermore, one of the input signals of the calculation unit 7f 7d with the switch closed, the output signal of the phase voltage detector 7e. By means of this controller is controlled by an overvoltage monitoring as follows:

p0032Is connected at the input X applied phase voltage is less than a predetermined control threshold, then the phase is senspannungs detector 7e via the switch 7d is located in the closed state of the computing unit 7f, so that the computing unit 7f generates the control signal s in such a way that a complete de-excitation of the generator is avoided.

p0033During this procedure the phase voltage in the regulation of Betriebsspannungskomparator monitored 7b to the operating voltage connection B + DC voltage to determine whether it + a predetermined upper limit UB_Max exceeds or not.

p0034Detects the operating voltage comparator 7b that the operating voltage at the terminal B + DC voltage to the predetermined upper limit UB +_Max exceeds, then it outputs a start signal for the timer 7c. This timer 7C is set to a time interval, which is dimensioned such that are typically compensated by a load dump voltage fluctuations caused again.

p0035If this state where 7e on the output of the phase voltage detector is engaged in the scheme and in which the operating voltage connection B + DC voltage to predetermined upper limit UB +_Max exceeds, for a period which is longer than the predetermined by the timer 7c time interval, then bring the timer 7c the switching element 7d in the open state. In this open state of the switching element 7d, the influence of the phase voltage is disabled in the scheme. As a result, the further regulation takes place essentially in function of the B + operating voltage connection present at the DC voltage, which is the arithmetic unit fed 7f on the operation voltage Istwertdetektor 7a.

p0036In this case the generator in the event of load shedding can indeed be completely de-energized, but is this usually only a loss of comfort is showing itself in a short voltage drop in the electrical system. However, it is advantageously prevents the occurrence of prolonged overvoltage and one caused by this surge damage to vehicle electrical system components.

p0037Is detected in the course of this deactivation of the phase voltage control intervention that the phase voltage is again greater than the 7e by the phase detector voltage set phase voltage intervention threshold and that the predetermined threshold value UB +_Max is not reached for the operating voltage connection B + operating voltage again, the intervention of the phase voltage is either released into the regulation immediately or after a predetermined time period by the switching element 7d is brought back to its conducting state.

p0038A development of the invention, the open state of the switch 7d, ie a disabled phase intervention in the regulation of signaling a controller using a lamp or a status flag.